In some circumstances, an MS of a wireless communication system can communicate more smoothly with a neighbor Base Station (BS) than a serving BS by reason of a change of its own position, a change of a radio environment, a change of the number of subscriber MSs within a cell, and so forth. In this case, the MS, the serving BS, and the neighbor BS recognize a change of a communication environment and perform a Handover (HO) procedure for establishing a new communication path such that the MS smoothly communicates. For example, if a strength of a signal of the MS received from the neighbor BS is greater than a strength of a signal received from the serving BS, the MS performs handover to a cell administered by the neighbor BS. In the following description, a serving cell denotes a cell administered by the serving BS, and a neighbor cell denotes the cell administered by the neighbor BS.
When performing handover to the neighbor cell, the MS needs neighbor cell information such as a frequency of the neighbor cell, a bandwidth, a cell IDentifier (ID), a preamble sequence index, and the like. Thus, the serving BS transmits information regarding its own neighbor cells to MSs located in its service area in order to help the MSs to handover.
In a general wireless communication environment, six to twelve neighbor cells can be located around one cell. Thus, an amount of neighbor cell information transmitted from a serving BS to an MS is not much, thus having no great influence on communication efficiency.
In a wireless communication environment where cells of service areas of different sizes are mixed, there are neighbor cells of service areas of the same size and neighbor cells of service areas of different sizes around one cell. For example, there are different neighbor macro cells and neighbor Femto cells around one macro cell.
In this case, there is a problem in that an amount of neighbor cell information transmitted from a serving BS to an MS increases, thus having bad influence on communication efficiency.
Also, the number of neighbor cells to which the MS can handover increases and thus, the MS can perform scanning throughout a serving cell area. While performing the scanning, the MS is interrupted in communication with the serving BS and thus, there is a problem that the scanning operation results in deterioration of communication efficiency.